[ion] Handle USBEnumeration event like USBPlug.

Change-Id: I70c1dc92fdba8e56508a1dce65ad30a771326a30

ion/include/ion/usb.h

@@ -5,7 +5,10 @@ namespace Ion {
 namespace USB {
 
 bool isPlugged();
+bool isEnumerated(); // Speed-enumerated, to be accurate
+
 void removeSoftDisconnect();
+
 void DFU();
 
 }

ion/src/device/events_keyboard.cpp

@@ -1,5 +1,4 @@
 #include <ion.h>
-#include "regs/otg.h"
 #include <assert.h>
 
 namespace Ion {
@@ -20,6 +19,7 @@ static bool sleepWithTimeout(int duration, int * timeout) {
 Event sLastEvent = Events::None;
 Keyboard::State sLastKeyboardState;
 bool sLastUSBPlugged = false;
+bool sLastUSBEnumerated = false;
 bool sEventIsRepeating = 0;
 constexpr int delayBeforeRepeat = 200;
 constexpr int delayBetweenRepeat = 50;
@@ -41,9 +41,12 @@ Event getEvent(int * timeout) {
       sLastUSBPlugged = usbPlugged;
       return Events::USBPlug;
     }
+
     // Second, check if the USB device has been connected to an USB host
-    if (OTG.GINTSTS()->getENUMDNE()) {
-      // The device is being enumerated, the speed enumeration is finished.
+    bool usbEnumerated = USB::isEnumerated();
+    bool previousUsbEnumerated = sLastUSBEnumerated;
+    sLastUSBEnumerated = usbEnumerated;
+    if (usbEnumerated && !previousUsbEnumerated) {
       return Events::USBEnumeration;
     }
 

ion/src/device/usb.cpp

@@ -13,6 +13,13 @@ bool isPlugged() {
   return Device::VbusPin.group().IDR()->get(Device::VbusPin.pin());
 }
 
+bool isEnumerated() {
+  /* Note: This implementation is not perfect. One would assume isEnumerated to
+   * return true for as long as the device is enumerated. But the GINTSTS
+   * register will be cleared in the poll() routine. */
+  return OTG.GINTSTS()->getENUMDNE();
+}
+
 void removeSoftDisconnect() {
   OTG.DCTL()->setSDIS(false);
 }